Increased multiplicity of Plasmodium falciparum infections and skewed distribution of individual msp1 and msp2 alleles during pregnancy in Ndiop, a Senegalese village with seasonal, mesoendemic malaria.

Abstract

Abstract. Pregnancy is associated with a greater susceptibility to Plasmodium falciparum infections, which may result in serious complications affecting both the mother and the fetus. To compare allelic diversity and multiplicity of infection in the same women during and outside pregnancy, we conducted a retrospective analysis of the monthly fingerprick blood samples collected during a longitudinal survey conducted in Ndiop, a Senegalese village with mesoendemic malaria. Merozoite surface protein-1 (msp1) block 2 and merozoite surface protein-2 (msp2) genotypes were determined for 308 blood samples collected from 20 women. Pregnancy was associated with a significantly higher prevalence of P. falciparum infection, higher parasite densities, and a higher multiplicity of infection. The highest multiplicity of infection was observed in the youngest pregnant women. Because of co-linearity, it was not possible to dissociate the impact of age from that of parity on multiplicity of infection. Some individual msp1 and msp2 alleles showed a highly skewed pregnancy-associated distribution. These results indicate that pregnancy is associated with increased permissiveness to a large number of clones, as well as with infection by specific genotypes.

Plasmodium falciparum genotypes in matched peripheral, placental and umbilical cord blood in an area characterised by unstable malaria transmission in eastern Sudan

“…This finding is characteristic of areas with unstable malaria transmission and has also been reported among pregnant women in Senegal (Schleiermacher et al, 2001). …”

Sequence Polymorphism, Segmental Recombination and Toggling Amino Acid Residues within the DBL3X Domain of the VAR2CSA Placental Malaria Antigen

“…Some of these studies used gel based PCR-RFLP analysis methods, and reported MOIs ranging from 1.5 to 4 [27], [28]. Another study used a quantitative Gene scan method and found a MOI of 5.6, suggesting that more sensitive methods are likely to detect higher MOIs [29]. The studies conflicted on the relationship between gravidity and MOI, with one study finding a negative correlation [29], and another finding no association [27].…”

Longitudinal Studies of Plasmodium falciparum Malaria in Pregnant Women Living in a Rural Cameroonian Village with High Perennial Transmission

“…19,[22][23][24] The number of genotypes has been found to decrease with gravidity in some studies, 23,24 but not in others. 19,25 In Ngali II, women were bitten at least once every other day by an infected mosquito.…”

“…19,20 This assay is a standard approach for studying genetic diversity of P. falciparum , 18,20 including in pregnant women. 19,[21][22][23][24][25] The number of alleles at the two loci was determined and the locus with the largest number of bands was used to estimate the MoI. In addition, the C-terminus of MSP-1 was sequenced and the MSP1-19 type was determined based on amino acids at position 294, 341, 349, 350, 351, and 366 of the MSP-1 42 3D7 reference sequence.…”